Light emitting device and leadframe thereof

Abstract

A LED leadframe for securing a LED chip includes a metallic base and an insulating layer. The metallic base includes a die bonding region and a peripheral region surrounding the die bonding region, and the die bonding region is for securing the LED chip. The insulating layer is disposed on the metallic base and located in the peripheral region to define the die bonding region. The insulating layer includes a bar-shaped insulating section disposed in the metallic base and corresponding to the die bonding region. The metallic base includes a first groove(s) defined corresponding to the die bonding region. The first groove(s) is/are filled with a thermally conductive filler. The invention improves the LED leadframe to allow heat conducting efficiencies of various regions of the base to be controllable and adjustable so as to reduce temperature differences among various regions of the base and thereby unify the temperature.

What is claimed is: 
     
       1. A LED leadframe configured for mounting a LED chip(s), wherein the LED leadframe comprises:
 a metallic base, comprising a die bonding region and a peripheral region surrounding the die bonding region; wherein the die bonding region is configured for mounting the LED chip(s) on an upper surface thereof, the die bonding region comprises a chip-mounted section(s) and a chip-blank section, and the chip-mounted section is defined by a projection of the LED chip on the upper surface; 
 an insulating layer, disposed on the metallic base and located in the peripheral region to define the die bonding region; 
 wherein the metallic base further comprises at least one first groove downwardly recessed in the metallic base from the upper surface and arranged corresponding to the chip-mounted section(s), the at least one first groove is filled with a thermally conductive filler in contact with the metallic base, and a thermal conductivity of the thermally conductive filler is larger than a thermal conductivity of the metallic base. 
 
     
     
       2. The LED leadframe according to  claim 1 , wherein a first connective channel is defined between adjacent two of the at least one first groove, and the first connective channel is filled with the thermally conductive filler. 
     
     
       3. The LED leadframe according to  claim 1 , wherein the amount of the at least one first groove is multiple, and the multiple first grooves are distributed to be axisymmetric or non-axisymmetric. 
     
     
       4. The LED leadframe according to  claim 1 , wherein the metallic base further comprises at least one second groove defined corresponding to the chip-blank section, the at least one second groove is filled with a second filler, and a specific heat capacity of the second filler is lower than a specific heat capacity of the metallic base. 
     
     
       5. The LED leadframe according to  claim 4 , wherein a second connective channel is defined between adjacent two of the at least one second groove, and the second connective channel is filled with the second filler. 
     
     
       6. The LED leadframe according to  claim 4 , wherein the at least one second groove extends into the peripheral region. 
     
     
       7. The LED leadframe according to  claim 4 , wherein the amount of the at least one second groove is multiple, and the multiple second grooves are distributed to be axisymmetric or non-axisymmetric. 
     
     
       8. A LED leadframe configured for securing a LED chip, wherein the LED leadframe comprises:
 a metallic base, comprising a die bonding region and a peripheral region surrounding the die bonding region; wherein the die bonding region is configured for securing the LED chip on an upper surface thereof, the die bonding region comprises a chip-mounted section and a chip-blank section; 
 an insulating layer, disposed on the metallic base and located in the peripheral region to define the die bonding region; 
 wherein the metallic base further comprises a second groove downwardly recessed in the metallic base from the upper surface and arranged corresponding to the chip-blank section, the second groove is filled with a filler in contact with the metallic base, and a specific heat capacity of the filler is smaller than a specific heat capacity of the metallic base and thereby the filler is capable of absorbing heat for enhancing a temperature in the chip-blank section to reduce a temperature difference between the chip-blank section and the chip-mounted section. 
 
     
     
       9. The LED leadframe according to  claim 8 , wherein the metallic base further comprises a first groove downwardly recessed in the metallic base from the upper surface and arranged corresponding to the chip-mounted section, the first groove is filled with a thermally conductive filler in contact with the metallic base, and a thermal conductivity of the thermally conductive filler is larger than a thermal conductivity of the metallic base. 
     
     
       10. A light emitting device comprising: LED chips, a package glue and a LED leadframe;
 wherein the LED leadframe comprises: 
 a metallic base, comprising a die bonding region and a peripheral region surrounding the die bonding region; wherein the die bonding region comprises chip-mounted sections and a chip-blank section, the LED chips are mounted on the chip-mounted sections of an upper surface of the die bonding region, and each of the chip-mounted sections is defined by a projection of a corresponding one of the LED chips on the upper surface; 
 an insulating layer, disposed on the metallic base and located in the peripheral region to define the die bonding region; 
 wherein the metallic base further comprises first grooves downwardly recessed in the metallic base from the upper surface and arranged corresponding to the chip-mounted sections, the first grooves are filled with a thermally conductive filler in contact with the metallic base, and a thermal conductivity of the thermally conductive filler is larger than a thermal conductivity of the metallic base; 
 wherein the package glue is filled in the die bonding region and covers the LED chips. 
 
     
     
       11. The light emitting device according to  claim 10 , wherein a first connective channel is defined between adjacent two of the first grooves, and the first connective channel is filled with the thermally conductive filler. 
     
     
       12. The light emitting device according to  claim 10 , wherein the first grooves are distributed to be axisymmetric or non-axisymmetric. 
     
     
       13. The light emitting device according to  claim 10 , wherein the metallic base further comprises one second groove defined corresponding to the chip-blank section, the second groove is filled with a second filler, and a specific heat capacity of the second filler is lower than a specific heat capacity of the metallic base. 
     
     
       14. The light emitting device according to  claim 13 , wherein a second connective channel is defined between adjacent two of the second grooves, and the second connective channel is filled with the second filler. 
     
     
       15. The light emitting device according to  claim 13 , wherein the second grooves extend into the peripheral region. 
     
     
       16. The light emitting device according to  claim 13 , wherein the second grooves are distributed to be axisymmetric or non-axisymmetric. 
     
     
       17. A light emitting device comprising: LED chips, a package glue and a LED leadframe;
 wherein the LED leadframe comprises: 
 a metallic base, comprising a die bonding region and a peripheral region surrounding the die bonding region, the die bonding region comprising chip-mounted sections and a chip-blank section, wherein the LED chips are mounted on the chip-mounted sections of an upper surface of the die bonding region; 
 an insulating layer, disposed on the metallic base and located in the peripheral region to define the die bonding region; 
 wherein the metallic base further comprises at least one second groove downwardly recessed in the metallic base from the upper surface and arranged corresponding to the chip-blank section, the at least one second groove is filled with a filler in contact with the metallic base, and a specific heat capacity of the filler is smaller than a specific heat capacity of the metallic base and thereby the filler is capable of absorbing heat for enhancing a temperature in the chip-blank section to reduce a temperature difference between the chip-blank section and the chip-mounted section; 
 wherein the package glue is filled in the die bonding region and covers the LED chips. 
 
     
     
       18. The light emitting device according to  claim 17 , wherein the metallic base further comprises first grooves downwardly recessed in the metallic base from the upper surface and arranged corresponding to the chip-mounted sections, the first grooves are filled with a thermally conductive filler in contact with the metallic base, and a thermal conductivity of the thermally conductive filler is larger than a thermal conductivity of the metallic base. 
     
     
       19. The LED leadframe according to  claim 1 , wherein the insulating layer comprises a bar-shaped insulating section disposed in the metallic base and corresponding to an insulating region in the die bonding region, and the metallic base is divided into two parts by the bar-shaped insulating section; the chip-mounted sections are distributed on two sides of the bar-shaped insulating section; and the metallic base is made of a metal. 
     
     
       20. The LED leadframe according to  claim 8 , wherein the insulating layer comprises a bar-shaped insulating section disposed in the metallic base and corresponding to an insulating region in the die bonding region, and the metallic base is divided into two parts by the bar-shaped insulating section; an amount of the chip-mounted section is multiple, and the multiple chip-mounted sections are distributed on two sides of the bar-shaped insulating section.